Engine throttle body hydrocarbon emissions reduction system

Abstract

A throttle body for an engine includes a throttle body housing, a throttle body plate supported by and rotatable within the throttle body housing, and a tab carried by the throttle body housing and movable between a first position in which the tab is in direct contact with the throttle body plate to prevent rotation of the throttle body plate and maintain the throttle body plate in a closed position, and a second position in which the tab is not in direct contact with the throttle body plate to permit rotation of the throttle body plate.

What is claimed is: 
     
       1. A throttle body for an engine, comprising:
 a throttle body housing defining a bore; 
 a throttle body plate supported by and rotatable within the throttle body housing; and 
 a tab carried by the throttle body housing and movable between (i) a first position in which the tab protrudes into the bore adjacent to the throttle body plate and is in direct contact with the throttle body plate to prevent rotation of the throttle body plate and maintain the throttle body plate in a closed position and (ii) a second position in which the tab is not in direct contact with the throttle body plate to permit rotation of the throttle body plate. 
 
     
     
       2. The throttle body of  claim 1 , wherein the tab is in the first position when the engine is off and in the second position when the engine is on. 
     
     
       3. The throttle body of  claim 1 , wherein the throttle body plate is configured to seal against the throttle body housing in the closed position. 
     
     
       4. The throttle body of  claim 1 , wherein the tab is configured to retract into a wall of the throttle body housing when in the second position and wherein the tab is configured to protrude from the wall when in the first position. 
     
     
       5. The throttle body of  claim 1  further comprising one or more additional tabs, each having the first and second position. 
     
     
       6. The throttle body of  claim 1 , wherein the tab is attached to a screw. 
     
     
       7. The throttle body of  claim 1  further comprising a sealing compound on at least a portion of the throttle body housing, the throttle body plate, or both. 
     
     
       8. The throttle body of  claim 1  further comprising one or more controllers programmed to command movement of the tab. 
     
     
       9. A throttle body for an engine comprising:
 a throttle body housing having a wall defining a bore; 
 a throttle body plate supported by the wall and rotatable within the bore; and 
 a rotary threaded sleeve engaged with the wall around a circumference of the bore, and including a tab configured to move axially, within the bore, toward the throttle body plate to engage the throttle body plate responsive to rotation of the rotary threaded sleeve in a first direction and axially away from the throttle body plate to disengage the throttle body plate responsive to rotation of the rotary threaded sleeve in a second direction opposite to the first direction. 
 
     
     
       10. The throttle body of  claim 9 , wherein the throttle body plate is configured to seal against the wall. 
     
     
       11. The throttle body of  claim 9 , wherein the tab is located at a first end of the rotary threaded sleeve. 
     
     
       12. The throttle body of  claim 9 , wherein the tab is configured to move in the first direction when the engine is shut off and in the second direction when the engine is turned on. 
     
     
       13. The throttle body of  claim 9  further comprising one or more controllers programmed to command movement of the tab. 
     
     
       14. The throttle body of  claim 9 , wherein the rotary threaded sleeve includes a plurality of threads gradually increasing in the first direction. 
     
     
       15. The throttle body of  claim 9  further comprising a sealing compound on at least a portion of the throttle body housing, the throttle body plate, or both. 
     
     
       16. A method for controlling an engine:
 responsive to the engine being shut off, commanding movement of a tab, carried by a throttle body housing, within a bore defined by the throttle body housing to directly engage a throttle body plate to prevent rotation of the throttle body plate and establish a seal between the throttle body plate and the throttle body housing by protruding into the bore adjacent to the throttle body plate, and 
 responsive to the engine being turned on, commanding movement of the tab within the bore to disengage the throttle body plate to permit rotation of the throttle body plate within the bore. 
 
     
     
       17. The method of  claim 16 , wherein the commanding movement of the tab includes actuating a stepper motor to rotate a rotatable threaded sleeve attached to the tab. 
     
     
       18. The method of  claim 17 , further including rotating the threaded sleeve away from the throttle body plate until a gap is formed between the tab and the throttle body plate, the gap being large enough to permit the rotation of the throttle body plate within the bore. 
     
     
       19. The method of  claim 16 , wherein the commanding movement of the tab includes actuating a stepper motor to retract the tab into the throttle body housing to disengage the throttle body plate. 
     
     
       20. The method of  claim 16 , wherein the commanding movement of the tab includes actuating a stepper motor to release the tab from the throttle body housing to directly engage the throttle body plate.